Most optical fiber splices intended for use in an operating environment, should be both strong and of low loss. The latter is a particularly important requirement for many systems where any unnecessary signal strength losses cannot be tolerated.
Achieving such fiber splices using technicians who are not required to be skilled or continuously trained, is problematic with existing methodologies, however. In addition, if the working space is confined or unstable as on-board ship, current techniques are not optimal.
Many current optical fiber splicing processes utilize a flame as the heat source for melting and fusing of two fiber ends. The flames, however, create thrust against the fibers, which must be considered or countered in order to maintain the fibers in their proper pre-splice axial alignment. Additionally, flame heat creates a differential heating of the fiber ends, resulting in a temperature gradient across the fiber cross-section. The gradient can deflect the fiber interior, which risks a weak and lossy bond at the transmitting core. Moreover, flame sources are inherently risky, particularly in confined spaces.
Laser heat sources have been employed in the prior art to avoid the noted problems which attend use of open flame fusion of optical fibers. In particular, low loss splices have been achieved in silica fibers using a pulsed CO2 laser in conjunction with fiber-gripping vacuum chucks, one being stationary and the other being manipulable in three dimensions. When the fiber ends are in axial alignment and tightly abutting relation, the laser is applied to effect the fusion.
Conventional high-strength fiber splicing also frequently requires that heated sulfuric acid be employed to strip the fiber coating prior to splicing. Conventional acid application methods, both horizontal and vertical, require large volumes of heated acid, typically 50 to 100 milliliters. The acid volume poses additional safety and health hazards to splicers. In addition, the conventional acid containment vessel requires a relatively long length of free fiber, ranging from 1 to 24 inches, which is cumbersome to use.